Mechanism and regulation of synthesis of aerobactin in Escherichia coli K12 (pColV-K30) J. B. NEILANDS Department of Molecular and Cellular Biology, University of California, 401 Barker Hall, Berkeley, CA 94720, U. S.A. Received May 19, 1991 Revision received November 18, 1991
Can. J. Microbiol. Downloaded from www.nrcresearchpress.com by Depository Services Program on 12/05/14 For personal use only.
Accepted November 21, 1991 NEILANDS, J. B. 1992. Mechanism and regulation of synthesis of aerobactin in Escherichia coli K12 (pColV-K30). Can. J. Microbiol. 38: 728-733. The aerobactin operon of the virulence plasmid pColV-K30 of Escherichia coli K12 consists of four genes for biosynthesis and one for transport of the siderophore. Regulation by iron occurs at the transcriptional level and is mediated by a ferrous iron binding protein designated Fur (ferric uptake regulation). The metallated Fur repressor binds at a palindromic dyad, the "iron box" operator, situated in the vicinity of the RNA polymerase attachment site of the promoter. Evidence suggests that the ferrous iron enters the C-terminal domain of Fur to cause a conformational change in the N-terminal part of the protein. This results in greatly enhanced affinity of the repressor for the operator. Key words: aerobactin, enterobactin, Fur repressor, regulation, siderophores, virulence. NEILANDS, J . B. 1992. Mechanism and regulation of synthesis of aerobactin in Escherichia coli K12 (pColV-K30). Can. J. Microbiol. 38 : 728-733. L'operon aerobactine du plasmide de virulence pColV-K30 d'Escherichia coli K12 comprend quatre genes pour la biosynthkse et un pour le transport du siderophore. La regulation du fer a lieu au niveau de la transcription et se fait par l'intermediaire d'une proteine designee Fur (regulation de la captation du fer) qui lie l'ion ferreux. Le represseur Fur metallise se lie a une sequence palindromique en forme de dyade, soit la sequence de l'operateur fixant la proteine Fur, l'opkrateur
Can. J. Microbiol. Downloaded from www.nrcresearchpress.com by Depository Services Program on 12/05/14 For personal use only.
Accepted November 21, 1991 NEILANDS, J. B. 1992. Mechanism and regulation of synthesis of aerobactin in Escherichia coli K12 (pColV-K30). Can. J. Microbiol. 38: 728-733. The aerobactin operon of the virulence plasmid pColV-K30 of Escherichia coli K12 consists of four genes for biosynthesis and one for transport of the siderophore. Regulation by iron occurs at the transcriptional level and is mediated by a ferrous iron binding protein designated Fur (ferric uptake regulation). The metallated Fur repressor binds at a palindromic dyad, the "iron box" operator, situated in the vicinity of the RNA polymerase attachment site of the promoter. Evidence suggests that the ferrous iron enters the C-terminal domain of Fur to cause a conformational change in the N-terminal part of the protein. This results in greatly enhanced affinity of the repressor for the operator. Key words: aerobactin, enterobactin, Fur repressor, regulation, siderophores, virulence. NEILANDS, J . B. 1992. Mechanism and regulation of synthesis of aerobactin in Escherichia coli K12 (pColV-K30). Can. J. Microbiol. 38 : 728-733. L'operon aerobactine du plasmide de virulence pColV-K30 d'Escherichia coli K12 comprend quatre genes pour la biosynthkse et un pour le transport du siderophore. La regulation du fer a lieu au niveau de la transcription et se fait par l'intermediaire d'une proteine designee Fur (regulation de la captation du fer) qui lie l'ion ferreux. Le represseur Fur metallise se lie a une sequence palindromique en forme de dyade, soit la sequence de l'operateur fixant la proteine Fur, l'opkrateur
